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Abstract:

An apparatus, kit and for permitting an underground pipeline to expand.
The apparatus comprises a sheet of material extending between first and
second sides and first and second ends. The sheet of material has a
plurality of slots extending from each of the first and second sides
towards each other. The kit comprises a front compressible body having a
shape corresponding to an outside radius of a pipe elbow and the sheet of
material wherein the sheet has a length and width sufficient to be
wrapped into a u-shape member extending around the compressible material
and the pipe elbow. The compressible material is formed of foam. The
method comprises providing the front compressible body proximate to an
outside bend in a pipe elbow and wrapping the sheet of material
thereabout with the front compressible body and pipe elbow therein.

Claims:

1. An apparatus for permitting an underground pipeline to expand
comprising a sheet of material extending between first and second sides
and first and second ends, said sheet of material having a plurality of
slots extending from each of said first and second sides towards each
other.

2. The apparatus of claim 1 wherein each slot extends to a distal end.

3. The apparatus of claim 2 wherein said distal ends of said slots
include strain relief bores.

4. The apparatus of claim 1 wherein said slots are arranged in matched
pairs extending from each of said first and second sides.

5. The apparatus of claim 4 wherein said matched pairs of slots are
substantially aligned with each other.

6. The apparatus of claim 1 wherein said slots extend to a distance
sufficient to leave a common gap distance therebetween.

7. The apparatus of claim 6 wherein said gap distance extend parallel to
said first and second sides.

8. The apparatus of claim 7 wherein said gap distance is selected to be
between 1 and 4 inches.

9. The apparatus of claim 1 wherein said sheet has first and second
surfaces wherein said slots have chamfered edges adjacent to said first
surface.

10. The apparatus of claim 1 wherein said sheet is formed of plastic.

11. The apparatus of claim 1 wherein said sheet has a thickness of
between 1/8 and 3/8 of an inch.

12. A kit for permitting an underground pipeline to expand comprising: a
rear compressible body having a shape corresponding to an outside radius
of a pipe elbow; and a sheet of material extending between first and
second sides and first and second ends, said sheet of material having a
plurality of slots extending from each of said first and second sides
towards each other, wherein said sheet has a length and width sufficient
to be wrapped into a u-shape member extending around said rear
compressible body and said pipe elbow.

13. The kit of claim 12 further comprising a front compressible body
corresponding to an inside radius of said pipe elbow.

14. The kit of claim 13 further comprising a plurality of straps sized to
extend around said sheet, said rear and said front compressible bodies
and said pipe.

15. The kit of claim 13 wherein said front and rear compressible bodes
are formed of foam.

16. A method for permitting an underground pipeline to expand comprising
providing a rear compressible body proximate to an outside radius in a
pipe elbow; wrapping a sheet of material extending between first and
second sides and first and second ends into a u-shaped cross section with
said rear compressible body and pipe elbow therein, said sheet of
material having a plurality of slots extending from each of said first
and second sides towards each other; and backfilling a soil material over
said sheet of material.

17. The method of claim 16 further comprising providing a front
compressible body corresponding to an inside radius of said pipe elbow.

18. The method of claim 17 further comprising wrapping a plurality of
straps around said sheet, said rear and said front compressible bodies
and said pipe.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates generally to pipeline protection in
general and in particular to a method and apparatus for protecting a pipe
during expansion and contraction.

[0003] 2. Description of Related Art

[0004] Pipe expansion and contraction under changes in temperature is a
common concern for many installations. In particular, the fluid which is
transported by the pipe may have an elevated temperature which will cause
the pipe to expand. It is well known that such expansion causes the pipe
to increase in length thereby potentially damaging the pipe. Commonly
such expansion of the pipe will be most prominent at the corners or
elbows of the pipe as well as within any installed expansion loops.

[0005] One common difficulty of such pipe expansion is in the case of
underground buried pipes. In such situations, the pipe will be covered
with a quantity of soil or other material so as to cover and conceal the
pipe from common viewing. Disadvantageously, when such backfill soil
material is placed around the pipe, it will also be commonly located
around the elbow or expansion joint, thereby limiting the degree to which
the pipe will be permitted to expand. An additional, it will be
appreciated that pipes buried underground may be subject to damage from
the surrounding and overlaid backfill soil due to impact or abrasion
during the aforementioned expansion and contraction such as, by way of
non-limiting example, scratching or chipping of the pipe coating
material.

[0006] One common approach to permitting a buried pipe to expand is to
provide a compressible material, such as, by way of non-limiting example,
expanded foam around the outside bend of the pipe to provide a region
into which the pipe may be permitted to expand. It will be appreciated
that such compressible material will commonly be located around the pipe
prior to backfilling and will therefore be covered and surrounded by the
overlying backfill soil.

[0007] Disadvantageously, as the compressible materials are commonly
covered by the backfill soil, such soil may enter any space between the
pipe and the compressible material during such backfilling operation.
Additionally, it will be appreciated that during cyclical expansion and
contraction of the pipe, additional soil may enter such spaces between
the pipe and the compressible material. Such soil entering the spaces
between the compressible material, as well as potentially entering the
voids in the compressible material itself reduces isolates the pipe from
the compressible material thereby reducing the effectiveness of such
material as well as the potentially reducing the compressibility of the
material itself.

SUMMARY OF THE INVENTION

[0008] According to a first embodiment of the present invention there is
disclosed an apparatus for permitting an underground pipeline to expand
comprising a sheet of material extending between first and second sides
and first and second ends. The sheet of material has a plurality of slots
extending from each of the first and second sides towards each other.

[0009] Each slot may extend to a distal end. The distal ends of the slots
may include strain relief bores. The slots may be arranged in matched
pairs extending from each of the first and second sides. The matched
pairs of slots may be substantially aligned with each other.

[0010] The slots may extend to a distance sufficient to leave a common gap
distance therebetween. The gap distance may extend parallel to the first
and second sides. The gap distance may be selected to be between 1 and 4
inches. The sheet may have first and second surfaces wherein the slots
have chamfered edges adjacent to the first surface.

[0011] The sheet may be formed of plastic. The sheet may have a thickness
of between 1/8 and 3/8 of an inch.

[0012] According to a further embodiment of the present invention there is
disclosed a kit for permitting an underground pipeline to expand
comprising a rear compressible body having a shape corresponding to an
outside bend of a pipe elbow and a sheet of material extending between
first and second sides and first and second ends. The sheet of material
has a plurality of slots extending from each of the first and second
sides towards each other wherein the sheet has a length and width
sufficient to be wrapped into a u-shape member extending around the rear
compressible body and the pipe elbow.

[0013] The kit may further comprise a front compressible body
corresponding to an inside radius of the pipe elbow. The kit may further
comprise a plurality of straps sized to extend around the sheet, the rear
and the front compressible bodies and the pipe. The front and rear
compressible bodes may be formed of foam.

[0014] According to a further embodiment of the present invention there is
disclosed a method for permitting an underground pipeline to expand
comprising providing a body of compressible material proximate to an
outside bend in a pipe elbow and wrapping a sheet of material extending
between first and second sides and first and second ends into a u-shaped
cross section with the compressible material and pipe elbow therein. The
sheet of material has a plurality of slots extending from each of the
first and second sides towards each other. The method may further
comprise backfilling a soil material over the sheet of material.

[0015] The method may further comprise providing a front compressible body
corresponding to an inside radius of the pipe elbow. The method may
further comprise wrapping a plurality of straps around the sheet, the
rear and the front compressible bodies and the pipe.

[0016] Other aspects and features of the present invention will become
apparent to those ordinarily skilled in the art upon review of the
following description of specific embodiments of the invention in
conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In drawings which illustrate embodiments of the invention wherein
similar characters of reference denote corresponding parts in each view,

[0018] FIG. 1 is a cross sectional view of an apparatus for permitting an
underground pipe to expand as installed around an underground pipe.

[0019] FIG. 2 is a cross sectional view of an apparatus for permitting an
underground pipe to expand as installed around an underground pipe.

[0020] FIG. 3 is a perspective view of the apparatus of FIG. 1.

[0021] FIG. 4 is a top plan view of the apparatus of FIG. 2.

[0022] FIG. 5 is a detailed cross-sectional view of the apparatus of FIG.
2 as taken along the line 4-4 of FIG. 3.

DETAILED DESCRIPTION

[0023] Referring to FIG. 1, an apparatus for permitting expansion of a
pipe 8 according to a first embodiment of the invention is shown
generally at 10. The apparatus comprises a sheet 12 of material having
plurality of slots 30 therein so as to be deformed into an arcuate
u-shape as illustrated in FIGS. 1 and 2. The sheet 12 is sized to extend
around both the top and bottom of the pipe 8 as well as a rear
compressible body 60 located between the sheet 12 and the pipe 8 as
illustrated in FIG. 2.

[0024] With reference to FIGS. 3 and 4, the sheet 12 has first and second
surfaces, 22 and 24, respectively and is formed of a flexible material
12. As illustrated in FIG. 4, the sheet 12 extends between first and
second ends, 14 and 16 respectively and first and second side edges, 18
and 20, respectively. The first and second side edges 18 and 20 may be
perpendicular to the first and second ends 14 and 16 so as to be
substantially rectangular, although it will be appreciated that other
shapes may also be utilized as well, such as, by way of non-limiting
example, trapezoidal or parallelogram. The sheet 12 has a length between
the first and second ends 14 and 16 selected to extend around the outside
elbow 6 of a pipe 8 as illustrated in FIG. 2. In particular, the sheet 12
may have a length selected to extend for a length greater than the
outside radius of the pipe 8 with a rear compressible body 60 located
therebetween as will be further described below. By way of non-limiting
example, the sheet 12 may have a length of up to 120 inches (3050 mm) or
more.

[0025] The sheet 12 also has a width between the first and second side
edges 18 and 20 sized to be folded into a u-shaped cross section as
illustrated in FIG. 3 sized to extend around the top and bottom of a pipe
8 with a rear compressible body 60 located therebetween. As illustrated
in FIG. 3, when folded into the u-shaped cross section, the sheet 12 will
have top and bottom substantially flat portions, 40 and 42, respectively
with an arcuate portion 44 therebetween. The arcuate portion 44 has a
radius, generally indicated at 46 corresponding to the radius of the pipe
8. By way of non-limiting example, for a pipe 8 having a radius of
approximately 4 inches (102 mm) a width of between 30 and 40 inches (762
and 1016 mm) has been found to be adequate.

[0026] As illustrated in FIG. 4, the sheet 12 includes a plurality of
slots 30 extending from each of the first and second side edges 18 and 20
in a direction generally towards each other. As illustrated in FIG. 4,
the slots 30 may extend substantially perpendicularly from the first and
second edges however it will be appreciated that the slots 3 may also
extend at an angle relative to the first and second side edges 18 and 20
to facilitate bending of the sheet 12 around a pipe elbow 6 as further
described below. Each slot 30 may include a strain relieving bore 32 at a
distal end thereof as are commonly known in the art. As illustrated in
FIG. 4, the slots define flaps 34 therebetween the purpose of which will
be more fully described below. The slots 30 extend from the first and
second side edges 18 and 20 at regular spaced apart intervals so as to
create substantially evenly sized flaps 34. By way of non-limiting
example, the slots 30 may be spaced along the first and second edges to
form flaps 34 having a width of between 6 and 24 inches (152 and 610 mm).
The slots 30 and bores 32 may have a width selected to assist in the
flaps 34 in overlapping each other as described below. In particular the
slots may have a width of up to 1/2 inch (12 mm) and a bore having a
diameter of up to 1 inch (25 mm).

[0027] The slots 30 are arranged so as to be substantially aligned with a
corresponding slot from the opposed side. As illustrated in FIG. 4, the
strain relieving bores 32 are spaced apart from each other by a gap
distance 36 along a center line 26 of the sheet. The slots 30 may each
have a common length so as to form a gap distance therebetween which is
common along the length of the sheet. The gap distance 36 will be
selected to maintain the sheet 12 as a cohesive article as well as to
provide flexibility of the sheet when applied to a pipe elbow 6 as
described below. In particular it has been found that a gap distance of
between 1 and 4 inches (25 and 102 mm) has been useful.

[0028] Turning now to FIG. 5, a cross sectional view of the slot as taken
along the line 4-4 is illustrated. The slot 30 may include a bottom
section 50 having edges substantially perpendicular to the first and
second surfaces 22 and 24. The slot 30 may also include a top portion 52
having chamfered edges as illustrated in FIG. 5 so as to facilitate
sliding of one flap 34 over another as will be more fully described
below. The sheet 12 may be formed of any suitable flexible material, such
as, by way of non-limiting example, plastics, such as polyurethane,
polyethylene or polyethylene terephthalate as well as natural or
synthetic rubbers, composite materials or impregnated fabrics. The sheet
12 may have any thickness suitable to support soil around the pipe 8 as
well as to remain flexible, such as, by way of non-limiting example,
between 1/8 and 1/2 inches (3 and 12 mm).

[0029] The rear compressible body 60 a body of a substantially
compressible material, such as foam or the like which may be formed to
conform to the shape of the pipe elbow. As illustrated in FIG. 2, the kit
may also include a front compressible body 62 formed of a similar
material to the rear compressible body 60 which may formed or otherwise
located proximate to an inside bend of the elbow.

[0030] In operation, a user may locate a pipe 8 having an elbow 6 within
an excavation. Thereafter a rear compressible body 60 may be located
around the outside radius of the elbow 6 as illustrated in FIG. 2. To
protect the rear compressible body 60 the sheet 12 may be folded about
the center line 26 into a u-shaped profile. Thereafter the u-shaped
profile may be curved as illustrated in FIG. 3 so as to overlap
successive flaps 34 onto each other. The sheet 12 may then be located
around the pipe elbow 6 and the front compressible rear compressible body
60. Optionally, a front compressible body 62 may be located proximate to
the inside radius of the elbow as well and the sheet 12 secured around
the pipe and compressible bodies with strapping 64, tape or the like.
Thereafter the pipe and sheet assembly may be covered with soil 4. When
positioned in such a manner, the pipe 8 will be permitted to expand by
compressing the rear compressible body 60 and to contract by moving away
from the sheet. It will be observed that during such contraction, the
sheet 12 will prevent soil and the like from entering any space between
the pipe 8 and the compressible body thereby ensuring that the pipe can
thereafter expand again. It will also be appreciated that the sheet 12
will serve to protect surface coating of the pipe from impacts with rocks
or the like during backfilling of the excavation as well as from abrasion
against the soil formation during cyclical expansion and contraction of
the pipe by isolating the pipe from such soil formations.

[0031] While specific embodiments of the invention have been described and
illustrated, such embodiments should be considered illustrative of the
invention only and not as limiting the invention as construed in
accordance with the accompanying claims.